Cat Calorie Calculator

Cat feeding runs on the same equation vets use for every species: resting energy requirement equals 70 times body weight in kilograms raised to the power of 0.75. That exponent is the important part — metabolism does not scale linearly with size, so a 6 kg cat does not need half again what a 4 kg cat does.

Resting requirement is what the cat burns doing nothing. Multiply by a factor for its situation and you get the daily requirement: 1.2 for a neutered adult, 1.4 for an intact one, 2.5 for a kitten. Neutering knocks about a quarter off, which is exactly why so many cats gain weight in the year after the operation.

Weight loss works differently, and getting it wrong is dangerous. The calculation is based on the target weight rather than the current one, then multiplied by 0.8 — because feeding a fraction of what an overweight cat currently needs still feeds it for being overweight.

1. Step 1 Resting energy requirement RER = 70 × weight_kg^0.75 For weight loss, use the target weight here rather than the current one.
2. Step 2 Daily requirement DER = RER × factor Neutered adult 1.2, intact 1.4, senior 1.1, kitten 2.5, weight loss 0.8.
3. Step 3 Convert to dry food cups = DER ÷ kcal_per_cup Typical dry cat food is 350–450 kcal per measured cup.
4. Step 4 Convert to wet food cans = DER ÷ kcal_per_can A 3 oz / 85 g can is usually 70–100 kcal.
5. Step 5 Check the pace of weight loss weekly% = (current − target) ÷ current ÷ weeks × 100 Must stay under 2% per week. Above that, the risk of hepatic lipidosis rises sharply.

Example: a 5 kg neutered adult cat. RER is 70 × 5^0.75 = 234 kcal, times 1.2 gives 281 kcal a day — about 0.8 cups of a 350 kcal/cup dry food, or roughly 3 cans of an 90 kcal wet food.

• The resting energy equation RER = 70 × kg^0.75 is the standard veterinary formula. Individual cats vary by up to 20% around it, so the output is a starting point to be adjusted by watching body condition.
• Activity multipliers are the widely-used clinical values: 1.2 for a neutered adult, 1.4 intact, 1.1 senior, 2.5 for a kitten under twelve months. Very active or outdoor cats need more; strictly indoor sedentary cats often need less than 1.2.
• Weight-loss calculations use the target weight as the basis, multiplied by 0.8. This is the standard clinical approach — using current weight would keep feeding the cat for the weight it is trying to lose.
• Safe weight loss for cats is 0.5 to 2% of body weight per week. Faster loss risks hepatic lipidosis, a serious and often fatal liver condition that cats are uniquely prone to. Any weight-loss plan should be supervised by a vet.
• Food energy values default to 350 kcal per cup of dry and 90 kcal per can of wet. Real products range from 300 to over 500 per cup, so read your own label — using the default when your food is denser is a common way to overfeed.
• A "cup" means a measured 8 fluid ounce cup. The scoop supplied in a bag of food frequently holds more than that.
• Pregnancy, lactation, hyperthyroidism, diabetes, chronic kidney disease and recovery from illness all change energy requirements substantially and are outside what this models.
• Treats and table food are not included in the daily figure. They should stay under 10% of total calories.